Control switch



Sept. 10, 19 9. J. P. SALFER CONTROL SWITCH Shams-Sh 1 Filed Dec. 22, 1928 V d 6 J3 a Sept. 10, 1929. SALFER 1,727,676

.CONTROL SWITCH Filed D60. 22, 1928 2 Sheets-Sheet 2 Elia-.3-

Patented Sept. 10, 1929.

UNl'l'El) STATES hit'hti'it JOHN P. SALFEB, GL3 MANKATO, MINNESOTA.

CONTROL SWITCH.

Application filed December 22-, 1928.

The invention relates to improvements in control switches and the present disclosure is directed more particularly to one which is operated by a thermostat and is intended for controlling passage of current through an electrical heating coil, more particularly the coil of an incubator or brooder.

It is the object of the invention toprovide a simple, compact and rather inexpensive switch mechanism which may be easily ad j usted to act at the desired temperature, will be sensitive, long-lived and continually efiicient.

With the foregoing in view, the invention resides in the novel subject matter hereinafter described and claimed, description being accomplished by reference to the accompanying drawings.

Fig. 1 is a perspective view showing the features of construction disposed at the rear of the base plate.

Fig. 2 is a perspective view illustrating primarily the parts located at the front of the base plate.

Fig. 3 is a longitudinal sectional view on line 33 of Fig. ,1.

4: is a' disassembled perspective view, certain partsibeing omitted.

The construction selected for illustration may be considered as preferred and while such construction will be herein specifically explained, it is to be understood that within the scope of the invention as claimed, variations may be made.

In the drawings above briefly described, the numeral5 denotesa horizontally elongated base having an integral upstanding post 6 at one end or" one of its longitudinal edges, said post being provided with upper and lower bearings 78. Threaded into an opening 9 in this end of the base 5 and projecting downwardly from said base, is a tube 10 whose lower end is provided with a yoke 11 in which a thermostat 12 is mounted, said thermostat being provided with an upstanding stem 13 which is slidable in the tube 10 and projects somewhat above the base. The upper'end of this stern passes through an openingl in a spring arm 15 which extends longitudinally ever the base Serial No. 327,953.

5, one end of this spring arm being tightly held against the base by means of base 16 on a second and relatively high post 17, said base 16 being secured to said base 5 by crews 18 which pass also through openings in the spring arm 15. Like the post 6, the upper end of the post 17 is provided with a bearing 19. In this bearing, a rock shaft 20 is mounted, the rear end of this rock shaft provided with a crank 21 which is connected by a link 22 with the upper end of a switch-operating arm 23. This arm is pivoted at 2% to the end of the spring arm 15 remote from the post 17 and while the major portion or said arm 23 is vertical, it is provided with a horizontal lower end which extends across the opening 1 1 in the spring arm 15. lChe front end of shaft 20 is provided with a downwardly projecting arm 25 carrying a clip 26 for a mercury switch 27, P

and whenever lever 23 is moved under the influence oi the stem 13 or by the spring 15, the said arm 23, the link 22 and the arm 21, turn the rock shaft 20 to swin arm 25, thereby causing opening or closing of the switch 27, as the case may be.

A bell crank 28 is disposed in a transverse plane at the end of the base 5 provided with the post 6, said bell crank being tulcrumed to this end of the base as indicated at 29. This bell crank is provided with one arm 30 behind the bearing 6 and with another arm 31 which underlies the spring 1 arm 15. An adjusting screw 32 is threaded through the bearing 8 and is provided at its front endwith an operating knob 33, the rear end of the screw abutting the arm 30 of the bell crank 28. By threading this screw further inward, the bell crank is so rocked as to raise the spring 15 any desired distance above the stem 13, so that said stem will not abut the lever 23 until the thermostat 12 has expanded a predetermined amount. As soon as the stem forces a ainst the arm or lever 23 however, it operates the latter and the parts 222120'25 to shift the switch 27 from closed to open position. W hen the temperature recedes and the thermostat cools and contracts sufliciently, the

stem 1?: lnwers and spring 15 TiilllTDS the parts to their initial positions, so that the switch 27 again closes.

Disposed in front of all of the parts above described, with the exception of the knob 23, the switch 2?, the clip 26 and the arm 25, is a vertical face plate 34 which is secured by screws or other desired means 35 to the front sides of the posts 617, said plate being formed with openings alined with all of the bearings 78l9. The arm 25 and associated parts are disposed at the front side of this base plate, as is also true of the adjusting knob 33 for the screw 32. Then too, a temperature indicator 36 is disposed at the front of the plate 3% and is eo-operable with ten'iperature indications 37 on said plate. The indicator 36 is carried by the front end of a rock shaft 38 whose rear end is provided with a crank 39 connected to the upper end of a link d0, the lower end of this link being pivotedto the free end of the spring arm 15. As the knob 33 is rotated to move the arm 23 into more or less close relation with the stem 13 of the thermostat 12, the parts -1039-38 move the indicator 36 along the indications 37 and by setting said indicator at the desired point, the entire structure is set for operation at the desired temperature.

It will be seen from the foregoing that unique provision has been made for carrying out the object of the invention. Attention is again invited to the fact however, that within the scope or said invention as claimed,

variations may be made.

I claim 1. A control switch comprising a spring arm anchored at one end and having an opening near its other end, a switch-operating arm pivoted to said other end of said spring arm and having a portion extending across said opening, an actuator movable through said. opening for swinging said switch-operating arm, and means for moving said spring arm in one direction and holding it at the position to which moved, whereby to vary the relation between said switclroperating arm and said actuator, the tension of said spring arm tending to move it in the other direction.

2. A control switch comprising an elongated base having an upstanding post at one end, a screw threaded through said post and extending transversely of said base, a bell crank tulcrumed on said end of said base and. having one end extending toward said post, the other end of said bell crank contacting with said screw whereby the latter may be utilized to efi'ect vertical movement of said one end of the crank, a spring arm extending longitudinally of said base and at one end secured to the latter, the other end of said spring arm lying upon said one end of said bell crank, a switch-operating arm pivoted on said other end of said spring arm, and an actuator for said switch-operating arm, the relation of said switch-operating arm with said actuator being variable by adjustment of the aforesaid screw and the consequent movement of the bell crank, spring arm and switch-operating arm.

3. A control switch comprising an elongated base having an upstanding post at one end, a screw threaded through said post and extending transversely of said base, a bell crank fulcrumed on said end of said base and having one end extending toward said post, the other end of said bell crank contacting with said screw whereby the latter may be utilized to effect vertical movement of said one end of the crank, a spring arm extending longitudinally of said base, a second post having a base resting on one end of said spring arm and secured to the first named base to anchor said one end of the spring arm, the other end of said spring arm lying upon said one end of said bell crank, a switch-operating arm pivoted upon said other end of said spring arm, a switchoperating member supported by said second post and linked to said switch-operating arm, and an actuator for said switchoperating arm, the relation of said switchoperating arm with said actuator being variable by adjustment of the aforesaid screw and the consequent movement of the bell crank, spring arm, and switelroperating arm.

4. A control switch comprising an elongated base having an upstanding post at one end, a screw threaded through said post and extending transversely of said base, a bell crank fulcrumed on said end of said base and having one end extending toward said post, the other end of said bell crank contacting with said screw whereby the latter be utilized to cfi'ect vertical movement of said one end of the crank, a spring arm extending longitudinally of said base and at one. end secured to the latter, the other end of said spring arm lying upon said one end of said bell crank, a switch-operating arm pivoted on said other end of said spring arm, an actuator for said switch-operating arm wit-h respect to which the latter is movable by adjustment of said screw and the consequent movement of hell crank and spring arm, a second post rising rigidly from the end of the base remote from the first named post, each post having a bearing, a rock shaft mounted in the bearing of the first named post, operatively connected. with said other end of said spring arm to be moved by the latter and provided with a temperature indicator, and a switch-operating rock shaft mounted in the bearing of the other post and operatively connected with said switch-operating arm.

5. A control switch comprising a vertical face plate, a base extending longitudinally behind the lower edge of said plate, said base being provided at its ends with upstanding posts behind said plate, each of said posts being provided with a bearing at its upper end and one of said posts being provided also with an additional bearing below its first named bearing, said plate having openings alined with said bearings, a rock shaft mounted in the bearing of the other post and having an arm at the front side of said plate, a gravity switch carried by said arm, an actuator movable with respect to said base, adjustable means behind said plate for establishing an operating connection between said actuator and said rock shaft, an adjuster for said adjustable means threaded through said additional bearing of said one post and having a knob at the front side of said plate, a rock shaft mounted in the other bearing of this post and having a temperature indicator at its front end disposed at the front side of said plate, and means operatively connecting the rear end of this shaft with a portion of said adjustable means which may be moved by said adjuster, said plate having temperature indications co-operable with said temperature indicator.

6. A control switch comprising a spring arm anchored at one end, a switch-operating arm pivoted to the other end of said spring arm, an actuator for swinging said switchoperating arm, and means for moving said spring arm in one direction and holding it at the position to which moved, whereby to vary the relation between said switch-operating arm and said actuator, the tension of said spring arm tending to move it in the other direction.

In testimony whereof I have hereunto affixed my signature.

JOHN P. SALFER. 

